David Davis from the College of Paramedics – the professional body representing ambulance personnel – said: “I’ve seen it ten, fifteen ambulances deep and personally waited for three, four, five, six hours to hand over.

“But the thing that’s remarkable about what’s happening now is this is not just a handful of isolated incidents. This is of absolutely enormous proportion and is presenting significant risk to patients.

He added: “Everything that we see suggests that the situation is getting worse.”

“As a group of professionals, paramedics can perhaps offer some solutions to the problem which is the whole system, the whole NHS and social care system coming under enormous strain and probably at the edge of being able to cope.”

BBC Radio Five Live Investigates asked 11 ambulance trusts in England and Wales how many operational hours were lost for either March or April.

Five ambulances had between them lost almost 14,000 operational hours.

Another three trusts said that ambulances had been delayed beyond the 15-minute target time on more than 48,000 separate occasions within a one-month period.

In one month at Heartlands hospital in Birmingham there were 102 cases where an ambulance was delayed for an hour or more.

There were almost 700 further cases where the delay lasted between 30 minutes and one hour.

The trust running Heartlands hospital said it has the busiest A&E department in the region.

A spokesperson said: “On some occasions up to 20 ambulances an hour are arriving.

“Problems arise when patients can’t be moved out of the department to other parts of the hospital because the hospital is full.”

The trust says it is investing in extra emergency care staff to help cope during those busy periods.

From the start of this month, hospitals will have to take patients off paramedics as quickly as possible or risk a financial penalty from the new Clinical Commissioners.

Hospitals will be fined £200 each time an ambulance is held up for more than 30 minutes and £1000 for more than an hour, with the money going back to the new health commissioners for investment in frontline services.